A MPEG video stream according to the MPEG2 video standard (ISO/IEC 13818-2) comprises intra frame coded pictures (I-pictures) and predictive coded pictures (B- and P-pictures). An I-picture comprises all the information required to produce the corresponding decoded picture. However, for decoding a P-picture, a preceding decoded P-picture or I-picture is required, while for decoding a B-picture a preceding decoded I-picture or P-picture and a decoded succeeding I-picture or P-picture are required. A MPEG stream is further composed of Groups of Pictures (GOP). Each GOP starts with an I-picture, followed by several B-pictures and P-pictures. During playback, pictures of a GOP are decoded starting from decoding the I-picture followed by decoding the successive B-pictures and P-pictures. In practice, in case of forward playback, at most two picture buffers are required to store temporarily two decoded pictures in order to decode a picture. However, reverse playback requires, in a simple straightforward embodiment, picture buffers for all pictures of a GOP, as for decoding the last picture in a sequence of pictures in a GOP, all preceding pictures should be available in decoded form. This has the disadvantage of requiring a large amount of memory, resulting in high costs.
A method of reverse playback of MPEG coded pictures, as well as an apparatus for performing the method is known from U.S. Pat. No. 5,892,882. When reverse playback is instructed, an MPEG decoder repeatedly, whenever it is required, produces coded pictures from the beginning of the GOP. Thus no decoded pictures need to be stored in picture buffers. Needless to say, this leads to either a reverse playback at a low speed or to reverse playback at normal speed, but with a high speed decoder.